1. Field of the Invention
The present invention relates to an image measurement device, a method for image measurement, and a computer readable medium storing a program for an image measurement device. Particularly, the present invention relates to an improvement of the image measurement device for measuring the size of the workpiece by detecting edges within the workpiece image obtained thereby.
2. Description of the Related Art
Generally, the image measurement device is a device for measuring the size of the workpiece based on the edge position of the workpiece image (Japanese patent publication No. 2009-300124, No. 2009-300125, No. 2010-019667). As usual, the workpiece is placed on a movable stage which can be moved in X-axis, Y-axis and Z-axis directions. It is possible to focus the workiece image by moving the movable stage in the Z-axis direction and adjust the position within a view of the image measurement device by moving the movable stage in the X-axis and Y-axis directions.
Since the workpiece image is strictly similar figure to the workpiece regardless of the position of the movable stage in the z-axis direction, it is possible to detect the actual size of the workpiece by measuring a distance from or an angle of the workpiece image. However, in the conventional image measurement device, it is hard to recognize relative position between the workpieces from the workpiece image for plurality of the workpieces placed on the movable stage, because visibility under the image measurement device is narrow. Therefore, there is a difficulty for an user to identify which workpiece a measurement result of the workpiece image have been measured from. Accordingly, it may be considered to display the measurement results along with each of the workpiece image over the plurality of the workpiece images in a wide field of view at a low magnification. However, if the measured sizes are displayed, it becomes difficult for an user to identify the measurement results.